Ship&#39;s davit



' n. H. ALEXANDER AND T. GRAHAM.

SHIPS DAVIT.

APPLICATION FILED ran. 20, I920- RENEWED JULY 23, I921.

1 ,389,338. I Patented Aug. 30, 1921.

2 SHEETS-SHEET I- n. H. ALEXANDER AND T. GRAHAM.

"SHIP'S DAVIT.

APPLICATION FILED FEB. 20, 1920. RENEWED JULY 23.1 921.

-1,389,338. I PatentedAug.30,1921.

2 SHEETS-SHEET 2.

UNITED STATES PATENT OFFICE.

ROBERT HILLS ALEXANDER, OF WILLINGTON QUAY, AND THOMAS GRAHAM, OF ISUNDERLAND, ENGLAND.

SHIPS DAVIT.

Specification of Letters Patent. Patented Aug. 30, 1921- Applicationfiled February 20, 1920. Serial No. 360,082. Renewed July 23, 1921.Serial No. 487,132;

To all whom it may concern:

Be it known that we, Ronnn'r HILLS ALEX- ANDER, residing at VVillingtonQuay, and THOMAS GRAHAM, residing at Sunderland, both in the county ofDurham England, subjects of the King of England, have invented certainnew and useful Improvements in Ships Davits, of which the following is aspecification.

This invention relates to improvements in ships davits of the kind inwhich the boat is.slung from a single curved davit arm pivoted at itslower end for swinging move ment inboard and outboard'and comprisingscrew gear for effecting such movement and suitable winding gear withtackle for raising and lowering the boat, the present inventionconsisting incertain novel features and combinations of parts ashereinafter described and claimed. 5

The improved ships davit constructed according to this inventioncomprises a single curved supporting arm or jib formed so that its upperor outer portion is comparatively narrow and slender as seentransversely to the longitudinal axis of the ship on which it is assumedto be mounted, and toward its lower end it is splayed out in bothdirections so as to form a laterallyem tended frame on which boatsupporting chocks may be mounted, there being ample space between thechocks to give support to the boat fore and aft; The arm is so curved asto clear the mid section of the boat when inboard and so that the lattermay have its center of gravity well inward of the axis of the arm. Thearm is pivoted on widely separated centers substantially beneath therespective chocks. It is provided with two pairs of chocks, one of eachpair substantially parallel with the arm, and the other of each pairextending forwardlyat an angle. The clearance between the arm and theboat is thus reduced to a minimum when the boat is in inboard position.The arm is mounted on a pivotal axis so that the point of suspension ofthe tackle is vertically above the center lin of the boat when inboard.

The tilting of the arm is advantageously effected by a screw gearoperating a sliding member connected by a link to the arm and the tackleby a winch carried by the said member.

Referring to the accompanying drawings illustrating an embodiment of theinvenionz- Figure 1. is a side elevation showing a davit in normalposition. V

Fig. 2 is a similar viewshowing the davit tilted outboard in thelaunching position.

Fig. 3 is a rear view.

Fig. 4 a side view'showing boats on two deeiks adapted to be operated byone davit, an

Fig. 5 is a plan showing means for connecting the .fall to the boat.

a designates the arm of jib pivotally conneoted to the deck at b andprovided at its upper end with a pulley 03, said arm beingadvantageously built up as shown in Fig. 3 of two members 6 f suitablyconnected by ties. a pair of brackets gg forming chocks for the boat,one of said bracket members g being preferably pivotally connected at gto its neighbor as shown, so that by releasing avpin i it can be droppedto give access to the bottom of the boat. Mounted in a frame 71 behindthe arm a; is a worm 7' adapted to be rotated by a handle 7' said wormhaving thereon a nut k connected to a can .riage Z which is suitablymounted on the frame it and connected to the arm a by a link m. On thecarriage is mounted a winch n from the drum of which a rope o'passesover a pulley (Z to a pulley block 7), the latter carrying a hook Q ofthe self-releasing type which is adapted to be connected to a slingattached to the boat, one form of sling bein shown by way of example inFig. 5 in which the sling ropes s are connected to lugs s pivoted on theboats keel.

In Fig. 4c the davit is shown mounted on a boat deck and another boatsupported on chocks t on the deck below. In this case a slot is cut inthe deck on which the davit stands to allow the tackle to be lowered andthe hook to be attached to the boat below after the upper one has beenlowered.

The screw gear 7' 7c and the winch may be Connected to the arm on eachside are power operated if desired, or provision may.

be made for both hand and power operation.-

In operation, when it is desired to lower the boat, the hook is attachedto the slings.

The falls are tautened by the winch 7' so as" to raise the boat rom thechocks. The arms are then moved outward on their pivots by the screwgear 7 g. The boat is then lowered by the winch.

A davit made in accordance with this invention can be easily and quicklymanipulated. The distance between the boat and the side of the vesselcan be altered during launching, and all danger resulting from thetackle jamming in the blocks is avoided, and further as shown two ormore boats can be lowered by one operation.

\Vhat we claim as our invention and deshe to secure by Letters Patent;of the United States is 1. In a shipsdavit the combination of a singlecurved davit arm broadened in each direction internally toward itspivotal axis, itscurvature being such that when inboard, the pivotalaxis is exterior of the vertical plane containing the longitudinalcenter line of the boat. andthe extremity of the arm in said verticalplane two laterally widely spaced bearings attached'tothe ships deckcarrying said pivotali axis, andliftingtackle for the boat carried bythe extremity of the arm.

2. Ina ship7s davit the combination of a singlecurved davit armbroadened laterally toward its pivotal axis, its curvature beingsuchthat when inboard, the pivotal axis is exterior of the verticalplane containing thelongitudinal center line of the boat and theextremity of the arm in said vertical plane, laterally spaced bearingscarrying said pivotal axis, and lifting tackle for the boat carried bythe extremity of the arm, together with a couple of pairs of chockscarried by the lateral extensions respectively .of said arm, one chockparallel to the arm and the other chock projecting therefrom at anangle, to support a boat thereon.

3. In a ships davit the combination of a single curved davit armbroadened laterally toward its pivotal axis, its curvature being suchthat when inboard the pivotal axis is exterior of the vertical planecontaining the longitudinal center line of the boat and the extremity ofthe arm in said vertical plane, laterally spaced bearings on the shipsdeck ROBERT HILLS ALEXANDER. THOMAS GRAHAM.

Vitnesses C. A. VVALTER, BERTI-IA M. Cnow.

